A new study at Karlstad University in Sweden shows that phthalates from PVC flooring materials is taken up by our bodies. Phthalates are substances suspected to cause asthma and allergies, as well as other chronic diseases in children. The study shows that children can ingest these softening agents with food but also by breathing and through the skin.

Phthalates are a group of chemical compounds that occur in construction materials and a great number of common consumer goods such as toys, cleaning solvents, packaging, etc. Phthalates are suspected of disrupting hormones and may be related to several chronic diseases in children, like asthma and allergies, as shown in earlier studies. Flooring materials using softened PVC contain phthalates and have previously been shown to be a significant source of phthalates in indoor dust. This new study was designed to investigate whether flooring materials using PVC and other housing-related factors, together with other individual factors, can be tied to the uptake of phthalates by infants.

Urine samples were taken from 83 randomly selected children between the ages of two and six months by the county council in Värmland in western Sweden. The prevalence of four types of phthalates in the urine was measured, and data were collected about flooring materials and the home, the family's lifestyle, and individual factors for the infants. The levels of certain phthalates (MBzP, a BBzP metabolite) proved to be higher in the urine of babies that had PVC materials on their bedroom floor. The levels of another phthalate metabolite related to DEHP were lower in two-month-old children if they were exclusively breastfed, with no supplements.

Earlier studies from the current group have shown that PVC flooring can be tied to the occurrence of phthalates in indoor dust, and that exposure for BBzP in indoor dust could be associated with allergic conditions in children. These new data thus show that the uptake of phthalates in infants can be related to flooring materials using softened PVC in the home. It should be pointed out that both DEHP and BBzP are banned for use in toys for small children owing to health risks.

"With this study as a basis, we can establish that there are other sources that should be taken into consideration in regard to the uptake of banned chemicals and that we do not only ingest them in our food," says Carl-Gustaf Bornehag, professor of public health at Karlstad University and leader of the study. The findings also show that phthalates can be taken up in different ways, both through food and probably through breathing and through the skin.

When manufacturing products, the coating technology is a key innovation driver for almost all areas of daily life - for example, for making scratch-proof displays for smart phones or anti-bacterial surfaces in refrigerators. Other coatings protect components from corrosion or aging, for example in a solar cell module or a car engine, without the end user noticing their existence. In industry today, wet chemical processes or vacuum plasma processes are primarily used for coating applications. Both have drawbacks. Vacuum units are expensive, limited to smaller components and applying a coating takes a relatively long time. Wet chemical processes often involve high resource and energy consumption with the corresponding environmental damage and can also cause difficulties in the handling of material combinations for lightweight construction such as plastics/ metals or aluminum/steel.

"There has to be another way", thought Dr. Jörg Ihde and Dr. Uwe Lommatzsch from the Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM in Bremen. Together with Plasmatreat GmbH, the IFAM team developed a new kind of plasma coating process that works at ambient pressure, that is to say, in an open atmosphere. "And that poses a major challenge", explains Jörg Ihde. "Because the pressure is more than 10,000 times higher and the absence of a vacuum reactor, we had to stop unwanted particles from forming and embedding in the coating. That was the key to developing robust and efficient industrial processes using the new plasma system.

The central element is a plasma nozzle. The nozzle is no bigger than a typical spray can. Yet it contains a highly complex coating system. "In the nozzle, an electrical discharge generates small flashes - a plasma that is expelled from the nozzle in the form of a jet. We systematically feed into the nozzle outlet those materials that are excited and fragmented in the plasma and then deposited out of the plasma jet as a functional nano-layer onto the surface", explains Uwe Lommatzsch. "We achieve extremely high deposition rates, enabling fast and cost-effective production processes to be realized."

The use of a nozzle allows the coating to be applied very precisely and only where it is needed, thus conserving resources. "We can control the processes so that the same nozzle can be used to apply coatings with various functionalities, for corrosion protection or for increasing or reducing adhesion, for instance", adds Jörg Ihde. Only very small amounts of coating material are required and practically all materials and material combinations can be coated. The process offers, in addition to the coating qualities and functionalities, even more benefits: it can be easily integrated into an inline production process, requires little space and is easy to automate, meaning it can be controlled via a robot. Yet another advantage: low investment costs and easy on the environment.  

The positive characteristics benefit industrial production: depositing an adhesion-promoting coating on a car window edge before gluing it in, to replace environmentally damaging chemicals or as a substitute for thick protective paint on printed circuit boards, which improves heat dissipation and hence prolongs service life. The process is already employed in the automotive industry and the energy sector to provide protection against corrosion and aging.